Would it be interesting to explore using all services in a round-robin fashion and fully take advantage of all free tiers? Not sure if it's too much trouble for the possible benefits.
Self-plug: NetToolKit Geo (https://www.nettoolkit.com/geo/about) offers very affordable map tiles (both raster and vector) and geocoding (plus a simple autocomplete feature for within the US). You can also configure whether your account automatically replenishes credits if they fall below a certain threshold, so you can have better control of spend.